The invention concerns a reciprocating piston with variable compression height for internal combustion engines in particular.
A reciprocating piston of the generic type is known from German Patent Specification No. 38 07 244.
An object of the invention is to improve the reciprocating piston of the generic type in such a way that a structural simplification of the temperature-dependent change in the compression height of the reciprocating piston is achieved.
The object is achieved according to the invention by utilizing a shape memory alloy spring for effecting temperature dependent changes in the compression height of the reciprocating piston.
The element operating as a function of temperature is formed by a spring which consists of a shape memory alloy and which interacts directly with the pressure limiting valve. Shape memory alloys which can be used to form the spring are known and available. This permits temperature-dependent change in the compression height of the reciprocating piston exclusively by the pressure limiting valve so that a structural simplification is achieved.
In an embodiment of the invention which is particularly advantageous in terms of structural simplification and with respect to assembly, the spring is located in a valve housing of the pressure limiting valve and in such a way that with increasing engine temperature, the preloading force on the valve body of the closing spring, also located in the valve housing, decreases.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.